Hi guys,
I'm new to Qlikview, and I'm having some problems with calculating a so called MTBF (Mean time between failures).
My input data is as follows:
| Loc ID | Maintenance type | Mileage | Date |
|---|
| 1 | CM | 10000 | 1-1-2010 |
| 1 | PM | 20000 | 1-5-2010 |
| 1 | CM | 30000 | 1-1-2011 |
| 1 | PM | 40000 | 1-10-2012 |
| 2 | CM | 10000 | 1-1-2010 |
| 2 | CM | 60000 | 1-1-2012 |
| 2 | PM | 80000 | 1-5-2012 |
| 3 | CM | 10000 | 1-1-2010 |
| 3 | PM | 30000 | 1-5-2010 |
| 3 | CM | 125000 | 13-12-2013 |
Now, the MTBF is determined by taking the average of either the mileages or the days passed between 2 CM maintenances. So the PM have to be left out of the equation. For example, LOC 1 had a CM at 10000 mile at date 1-1-2010. Its next CM was done at a mileage of 30000 at 1-1-2011. This means it has an MTBF of 20000 miles or 365 days. Furthermore, the latest CM date has to be displayed for each loc. Now I've been trying to do so with the Date(Max("Date") expression, but I'm unsure on how to calculate the amount of days between 2 CM's, let alone averaging all those days into a single number (the MTBF).
Hopefully someone can be of assistance here? Just point me in the right direction!
With regards,
Stijn
